In a digital still camera or a video camera, technologies for detecting distances for auto focusing (AF) are known. With regard to such technologies for detecting distances for AF, Japanese Patent Application Laid-Open No. 2002-314062 (hereinafter, referred to as Patent Literature 1) proposes a solid-state imaging device in which a part of pixels of an imaging device have a ranging function and the detection is made by a phase difference system.
The phase difference system is a method in which optical images which pass through different regions on a pupil of a camera lens are compared and triangulation using a stereo image is used to detect the distance.
In such a method, differently from the case of a conventional contrast system, it is not necessary to move the lens in order to carry out ranging, and thus, AF at high speed with high precision is possible. Further, real-time AF when moving images are taken is possible.
In Patent Literature 1 mentioned above, as a structure of a ranging pixel, a structure in which a microlens and multiple photoelectric conversion units thereunder are provided is disclosed.
This enables selective introduction of light which passes through a predetermined region on the pupil of the camera lens to the photoelectric conversion unit to carry out ranging.